Casinos are multi-billion dollar industries. Even though legalized gambling is a relatively young industry in this country, it continues to grow.
A necessary element for an effective casino operation is an efficient casino management and security system. Casinos spend substantial amounts of money to observe gamblers, dealers and others in the casino, using both electronic surveillance equipment and live personnel. Electronic surveillance usually takes the form of electronic camera globes or visible cameras (collectively cameras) which blanket the walls and ceilings of the casinos. These cameras generate enormous amounts of data, which has conventionally been stored on videotapes for possible later retrieval.
In most instances, cameras are stationed in areas where at least some part of the image frame being taped does not change often. For example, a camera may be stationed outside a vault or door in a stairwell. It is only when an action occurs, such as someone enters the vault or crosses a door in the stairwell that a portion of the image frames changes, and even then other portions of the image frame do not change.
Since the image frames change infrequently, it is desirable to use image compression to lower the transmission and storage requirements. Once image frames have been compressed, it is still desirable to be able to further process the compressed image frames to determine if an event has occurred.
For example, it is desirable to be able to detect that the image frames have changed due to a change in the field of view (e.g., someone crossing through the field of view) without having to decompress the previously compressed image frames. The present invention provides a mechanism for detecting that a change in the field of view previously occurred in the data associated with sequentially stored frames without having to decompress image frames and also provides several mechanisms for reacting to the detection of the change.